Epidemiological
studies are a key element of the disease control strategies of the World Health
Organization (WHO). By monitoring disease patterns over time, the WHO’s
Department of Vaccines and Immunization is able to plan vaccination policies to
achieve the greatest impact. Epidemiological surveys are also important in
assessing the success of these policies and any effects that they may have on
emerging strains and variants of the causative organisms of various diseases.
Measles is among
those infectious diseases that are currently the subject of WHO epidemiological
assessments. Although the control of measles is improving globally, significant
numbers of susceptible individuals are still to be found within target
populations. By identifying and assessing the proportion of these susceptible
individuals, the WHO is able to devise additional strategies aimed at promoting
wider uptake of the measles vaccine in at-risk populations.
One of the
responsibilities of the WHO’s Global Advisory Committee on Vaccine Safety is
the assessment of claims received from researchers that specific vaccines may
be causally linked to particular adverse events. In order to carry out a
thorough evaluation of the situation and either support or refute such claims,
a sound understanding of the epidemiological principles is essential. The
ability to interpret the complex data that may be generated by the
investigations is also required.
Epidemiological
assessments are, thus, a vital component of the work of the WHO in both
industrialised and developing regions, and are critical to any attempts to
improve worldwide control of infectious diseases.